U.S. patent application number 11/466902 was filed with the patent office on 2008-02-28 for diesel combustion mode switching control strategy and model.
Invention is credited to Qian Chen, Charles H. Folkerts.
Application Number | 20080047523 11/466902 |
Document ID | / |
Family ID | 39112189 |
Filed Date | 2008-02-28 |
United States Patent
Application |
20080047523 |
Kind Code |
A1 |
Chen; Qian ; et al. |
February 28, 2008 |
DIESEL COMBUSTION MODE SWITCHING CONTROL STRATEGY AND MODEL
Abstract
A combustion mode switching control system for diesel engines is
provided. The system includes, a switch determination module that
initiates a switch request to switch between at least one of a
premixed compression ignition (PCI) mode and a diesel combustion
mode based on engine speed and at least one of fuel quantity and
torque; a transition module that commands the at least one of the
PCI mode and the diesel combustion mode based on the switch
request; and a control module that controls at least one of target
airflow desired fuel quantity and desired fuel injection timing
based on the command.
Inventors: |
Chen; Qian; (Rochester,
MI) ; Folkerts; Charles H.; (Troy, MI) |
Correspondence
Address: |
GENERAL MOTORS CORPORATION;LEGAL STAFF
MAIL CODE 482-C23-B21, P O BOX 300
DETROIT
MI
48265-3000
US
|
Family ID: |
39112189 |
Appl. No.: |
11/466902 |
Filed: |
August 24, 2006 |
Current U.S.
Class: |
123/295 ;
123/27R; 123/305; 701/103 |
Current CPC
Class: |
F02D 41/3035 20130101;
F02D 2200/0402 20130101; F02D 41/2422 20130101; Y02T 10/128
20130101; F02D 41/40 20130101; F02D 41/18 20130101; F02D 41/3064
20130101; F02D 41/0002 20130101; F02B 69/00 20130101; F02D 41/3076
20130101; Y02T 10/12 20130101; F02D 41/0057 20130101 |
Class at
Publication: |
123/295 ;
123/305; 701/103; 123/27.R |
International
Class: |
F02B 17/00 20060101
F02B017/00; F02B 1/12 20060101 F02B001/12; F02B 5/00 20060101
F02B005/00; G05D 1/00 20060101 G05D001/00 |
Claims
1. A combustion mode switching control system for diesel engines,
comprising: a switch determination module that initiates a switch
request to switch between at least one of a premixed compression
ignition (PCI) mode and a diesel combustion mode based on engine
speed and at least one of fuel quantity and torque; a transition
module that commands the at least one of the PCI mode and the
diesel combustion mode based on the switch request; a control
module that controls at least one of target airflow, desired fuel
quantity, and desired fuel injection timing based on the command;
and an air estimation module that determines a current status of
air flowing into the engine and wherein the transition module
commands the at least one of the PCI mode and the diesel combustion
mode based on the status.
2. (canceled)
3. The system of claim 1 wherein the air estimation module
determines the current status of the airflow based on whether a
percentage of air flowing from exhaust gas recirculation (EGR) is
sufficient to allow a switch to occur.
4. The system of claim 1 wherein the air estimation module
determines the current status of the airflow based on at least one
of fuel quantity, torque, engine speed, mass airflow, boost
pressure in the intake manifold, temperature in the intake
manifold, and exhaust pressure.
5. The system of claim 1 wherein the transition module commands at
least one of a diesel combustion to PCI transition mode and a PCI
to diesel combustion transition mode after receiving the switch
request and until at least one of the status indicates that the
airflow is sufficient to accommodate the switch request and a
subsequent switch request is received indicating to switch back to
a previous mode.
6. The system of claim 1 wherein the control module controls target
airflow, desired fuel injection quantity, and desired fuel
injection timing based on the mode, engine speed, and at least one
of actual fuel injection quantity and torque.
7. The system of claim 6 wherein the control module controls target
airflow, desired fuel injection quantity, and desired fuel
injection timing during the PCI mode and the diesel combustion mode
based on separate target airflow, desired fuel injection quantity,
and desired fuel injection timing lookup tables for each of the PCI
and wherein the lookup tables are indexed by engine speed and at
least one of actual fuel injection quantity and torque.
11. The system of claim 5 wherein the control module controls the
target airflow, desired fuel injection quantity, and desired fuel
injection timing during the diesel combustion to PCI transition
mode and the PCI to diesel combustion transition mode based on
desired torque, actual fuel quantity, engine speed, mass airflow,
and injection timing.
12. A method of switching between a premixed compression ignition
mode (PCI) and a diesel combustion mode for diesel engines,
comprising; initiating a switch request to switch between at least
one of a premixed compression ignition (PCI) mode and a diesel
combustion mode based on engine speed and at least one of fuel
quantity and torque; determining an airflow status based on airflow
operating conditions of the engine; commanding at least one of the
PCI mode and the diesel combustion mode based on the switch request
and the airflow status; and controlling at least one of target
airflow, desired fuel quantity, and desired fuel injection timing
based on the commanded mode.
13. (canceled)
14. The method of claim 12 comprising commanding at least one of a
diesel combustion to PCI transition mode and a PCI to diesel
combustion transition mode after initiating the switch request.
15. The method of claim 12 comprising: determining the target
airflow based on the mode, engine speed, and at least one of actual
fuel quantity and torque; and determining the fuel injection timing
based on the mode, engine speed, and at least one of actual fuel
quantity and torque.
16. The method of claim 14 comprising determining the desired fuel
quantity based on desired torque, engine speed, mass airflow,
injection timing, and at least one of actual fuel quantity and
torque when the mode is commanded to the diesel combustion to PCI
transition mode and the PCI to diesel combustion transition
mode.
17. The method of claim 14 comprising determining the desired fuel
quantity during the diesel combustion to PCI transition mode and
the PCI to diesel combustion transition mode, wherein the
determining comprises: estimating a torque value based on the
current combustion mode, actual fuel quantity, mass airflow,
injection time, and engine speed; determining a difference between
the estimated torque and a desired torque; determining a fuel
adjustment value based on the difference and engine operation
parameters; and adding the fuel adjustment value to the actual fuel
quantity to achieve the desired fuel quantity.
18. The method of claim 12 the determining the airflow status is
further based on at least one of engine speed, fuel quantity,
torque, mass airflow, boost pressure in an intake manifold of the
engine, temperature in the intake manifold, and exhaust
pressure.
19. The method of claim 12 the determining of airflow status
comprising: estimating a percentage of exhaust gas recirculation
(EGR) flowing into an intake manifold of the diesel engine;
estimating a percentage of oxygen in the intake manifold; computing
a target exhaust gas recirculation level for the intake manifold;
computing a target of oxygen level for the intake manifold; and
setting the airflow status based on a comparison of the estimated
percentage of EGR and the target EGR and a comparison of the
estimated percentage of oxygen and the target oxygen.
20. The method of claim 12 comprising: determining the target
airflow based on the mode, engine speed, and at least one of actual
fuel quantity and torque; and determining the desired fuel quantity
based on the mode, engine speed. and at least one of actual fuel
quantity and torque.
21. The method of claim 12 comprising: determining the desired fuel
quantity based on the mode, engine speed, and at least one of
actual fuel quantity and torque; and determining the desired fuel
injection timing based on the mode, engine speed, and at least one
of actual fuel quantity and torque.
Description
FIELD OF THE INVENTION
[0001] The present disclosure relates to methods and systems for
controlling fuel injection of a diesel combustion engine.
BACKGROUND OF THE INVENTION
[0002] The statements in this section merely provide background
information related to the present disclosure and may not
constitute prior art.
[0003] Traditionally, there have been two primary forms of
reciprocating piston or rotary internal combustion engines: diesel
and spark ignition engines. While these engine types have similar
architecture and mechanical workings, each has distinct operating
properties. For example, to initiate combustion, spark ignition
engines supply an air/fuel mixture to the engine cylinder while
controlling spark timing. In contrast, diesel engines compress air
in the cylinder while controlling fuel injection timing to initiate
the start of combustion.
[0004] One of the major advantages that the diesel engine has over
the pre-mixed charge spark-ignited engine is higher thermal
efficiency. This is generally due to the higher compression ratio
and leaner combustion operation provided by the diesel engine. One
trade-off to the higher thermal efficiency of the diesel engine is
that it is more difficult or expensive to achieve the same tailpipe
NO.sub.x emission levels as does the spark-ignited engines. This is
due to the lean air/fuel control nature of the diesel engine.
[0005] Premixed Compression Ignition (PCI) is an advanced diesel
combustion technique that has great potential for reducing diesel
engine emissions. With PCI, fuel is injected into the combustion
chamber of the cylinder much earlier in the combustion stroke than
would be done for diesel combustion. The desired fuel amount is
supplied significantly before the piston reaches the compression
top dead center (TDC). The early injected fuel is mixed
sufficiently with the air before the piston reaches the compression
TDC. Thus, the technique provides a lean and well mixed state of
the air/fuel mixture before ignition.
[0006] However, PCI combustion is limited to low-load operating
conditions. Therefore, during other operating conditions diesel
combustion is required. Because PCI combustion and diesel
combustion have different requirements for the exhaust gas
recirculation (EGR) percentage, the air/fuel ratio, and the fuel
injection timing, the problem of how to switch smoothly between
these two combustion modes becomes a concern. Excessive smoke,
NO.sub.x, and combustion noise will result from lack of effective
combustion mode switching control,
SUMMARY OF THE INVENTION
[0007] Accordingly, a combustion mode switching control system for
diesel engines is provided. The system includes a switch
determination module that initiates a switch request to switch
between at least one of a premixed compression ignition (PCI) mode
and a diesel combustion mode based on engine speed and at least one
of fuel quantity and torque. A transition module commands at least
one of the PCI mode and the diesel combustion mode based on the
switch request. A control module controls at least one of target
airflow, desired fuel quantity, and desired fuel injection timing
based on the command.
[0008] In other features, a method of switching between a premixed
compression ignition mode (PCI) and a diesel combustion mode for
diesel engines is provided. The method includes: initiating a
switch request to switch between at least one of a premixed
compression ignition (PCI) mode and a diesel combustion mode based
on engine speed and at least one of fuel quantity and torque;
commanding at least one of the PCI mode and the diesel combustion
mode based on the switch request; and controlling at least one of
target airflow, desired fuel quantity, and desired fuel injection
timing based on the commanded mode.
[0009] Further areas of applicability will become apparent from the
description provided herein. It should be understood that the
description and specific examples are intended for purposes of
illustration only and are not intended to limit the scope of the
present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The drawings described herein are for illustration purposes
only and are not intended to limit the scope of the present
disclosure in any way.
[0011] FIG. 1 is a functional block diagram of a diesel engine.
[0012] FIG. 2 is a cross-sectional view of a cylinder of a diesel
engine.
[0013] FIG. 3 is a dataflow diagram of a diesel combustion mode
switching control system.
[0014] FIG. 4 is a diagram illustrating mode transitions.
[0015] FIG. 5 is a state transition diagram illustrating the
coordination of combustion mode switching,
[0016] FIG. 6 illustrates an exhaust gas recirculation control
model.
[0017] FIG. 7 is illustrates a torque control model.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] The following description is merely exemplary in nature and
is not intended to limit the present disclosure, application, or
uses. It should be understood that throughout the drawings,
corresponding reference numerals indicate like or corresponding
parts and features. As used herein, the term module refers to an
application specific integrated circuit (ASIC), an electronic
circuit, a processor (shared, dedicated, or group) and memory that
executes one or more software or firmware programs, a combinational
logic circuit, and/or other suitable components that provide the
described functionality.
[0019] Referring now to FIG. 1, an exemplary diesel engine system
10 is schematically illustrated. It is appreciated that the diesel
engine system 10 is merely exemplary in nature and that the diesel
combustion mode switching control strategy described herein can be
implemented in various diesel engine systems. The diesel engine
system 10 includes a diesel engine 12, an intake manifold 14, a
common rail fuel injection system 16 and an exhaust system 18. The
exemplary engine 12 includes six cylinders 20 configured in
adjacent cylinder banks 22,24 in V-type layout. Although FIG. 1
depicts six cylinders (N=6), it can be appreciated that the engine
12 may include additional or fewer cylinders 20. For example,
engines having 2, 4, 5, 8, 10, 12 and 16 cylinders are
contemplated.
[0020] Air is drawn into the intake manifold 14, is distributed to
the cylinders 20 and is compressed therein. FIG. 2 illustrates a
cylinder 20 in more detail. Fuel is injected into an intake port 31
of the cylinder 20 and/or directly into the cylinder 20 by the
common rail injection system 16 (FIG. 1). The heat of the
compressed air ignites the air/fuel mixture. An intake valve 32
selectively opens and closes to enable the air to enter the
cylinder 20. The intake valve position is regulated by an intake
camshaft (not shown). A fuel injector 33 injects fuel into the
cylinder 20. The fuel injector 33 is controlled to provide a
desired air-to-fuel (A/F) ratio within the cylinder 20 at a time
and quantity determined by the diesel combustion mode switching
control strategy. An additional fuel injector shown in phantom at
34 may be provided at or near the intake port 31 of the cylinder 20
and may be similarly controlled according to the diesel combustion
mode switching control strategy.
[0021] A piston 35 compresses the A/F mixture within the cylinder
20. The compression of the hot air ignites the fuel in the cylinder
20, which drives the piston 35. The piston 35, in turn, drives a
crankshaft (not shown) to produce drive torque. Combustion exhaust
within the cylinder 20 is forced out an exhaust port 36 when an
exhaust valve 37 is in an open position. The exhaust valve position
is regulated by an exhaust camshaft (not shown). Although single
intake and exhaust valves 32,37 are illustrated, it can be
appreciated that the engine 12 can include multiple intake and
exhaust valves 32,37 per cylinder 20.
[0022] Referring back to FIG. 1, the exhaust gases are exhausted
from the cylinders 20 and into the exhaust system 18. The exhaust
system 18 includes exhaust manifolds 28,30, exhaust conduits 27,29
a catalyst 38, and a diesel particulate filter (DPF) 40. First and
second exhaust segments are defined by the first and second
cylinder banks 22,24. The exhaust manifolds 28,30 direct the
exhaust segments from the corresponding cylinder banks 22,24 into
the exhaust conduits 27,29. In some instances, the diesel engine
system 10 can include a turbo 26 that pumps additional air into the
cylinders 20 for combustion with the fuel and air drawn in from the
intake manifold 14. The exhaust is directed into the turbo 26 to
drive the turbo 26. A combined exhaust stream flows from the turbo
26 through the catalyst 38 and the DPF 40. The DPF 40 filters
particulates from the combined exhaust stream as it flows to the
atmosphere.
[0023] In some instances, the diesel engine system can include an
exhaust gas recirculation (EGR) system (not shown). An EGR system
includes an EGR valve (not shown) that regulates exhaust flow back
into the intake manifold 14. The mass of exhaust that is circulated
back into the intake manifold 14 assists to reduce the temperature
of the air in the manifold 14 and affects engine torque output.
[0024] A controller 42 regulates operation of the diesel engine
system 10 according to the diesel combustion mode switching control
strategy of the present disclosure. More particularly, the
controller 42 determines if a switching between PCI and
conventional diesel combustion is desired and controls the engine
to switch between the combustion modes accordingly. The controller
42 communicates with an intake manifold boost pressure (boost)
sensor 44, a mass airflow (MAF) sensor 45, an engine speed sensor
46, and an intake manifold temperature sensor 47. The boost sensor
44 generates a signal indicating the air pressure within the intake
manifold 14. The MAF sensor 45 generates a MAF signal based on the
flow of air into the engine 12. The engine speed sensor 46
generates a signal indicating engine speed (RPM). The intake
manifold temperature sensor 47 generates a temperature signal based
on the temperature of air in the intake manifold 14. An exhaust
pressure sensor 48 generates an exhaust pressure signal based on
pressure of the exhaust flowing from the turbo 26.
[0025] Referring now to FIG. 3, a dataflow diagram illustrates an
embodiment of a diesel combustion mode switching control system 49
that may be embedded within the controller 42. Various embodiments
of diesel combustion mode switching control systems 49 according to
the present disclosure may include any number of sub-modules
embedded within the controller 42. The sub-modules shown may be
combined and/or further partitioned to similarly control the
combustion mode. In various embodiments, the controller 42 of FIG.
3 includes a switch determination module 50, a transition module
52, an air/EGR estimation module 54, and an air/fuel control module
56.
[0026] The switch determination module 50 receives as input engine
operating parameters such as engine speed 58 and an actual fuel
quantity 57 (determined by other sub-modules within controller 42).
The switch determination module 50 determines whether a transition
between the PCI mode and the diesel combustion mode is desired
based on the engine operating parameters. If a transition is
desired, the switch determination module 50 outputs a switch
request 60 to the transition module 52. The air/EGR estimation
module 54 receives as input engine operating parameters such as
engine speed 58, the actual fuel quantity 57, mass airflow 70,
boost pressure in the intake manifold 72, temperature in the intake
manifold 74, and exhaust pressure 76. The air/EGR estimation module
54 determines if the air/EGR requirement for the PCI or diesel
combustion is met. The air/EGR requirement estimation module
outputs an air/EGR condition 78 to the transition module 52.
[0027] The transition module 52 receives as input the switch
request 60 and the air/EGR condition 78. The transition module 52
coordinates when and how to transition between the combustion modes
based on the conditions of air (if going to diesel combustion) or
EGR (if going to PCI). Once the transition module 52 determines the
proper mode to transition to, a desired mode 80 is output to the
air/fuel control module 56. The air/fuel control module 56 receives
as input the mode 80 and engine operating parameters such as engine
speed 58, actual fuel quantity 57, mass airflow 70, actual
injection time 82, and desired torque 84. The air/fuel control
module 56 determines how to control transitions between modes and
during operation in the PCI mode and the diesel combustion mode.
More specifically, the air/fuel control module 56 controls the air
target 86, fuel injection quantity 88, and the desired timing 90.
The details of the diesel combustion mode switching control system
49 will be described in more detail below.
[0028] Referring now to FIG. 4, the switch determination module 50
of FIG. 3 will be discussed in more detail. The switch
determination module 50 determines if a switching between the PCI
mode and the diesel combustion mode is desired. The strategy is
designed to optimize the goals of minimizing the switching between
the two combustion modes and maximizing the PCI combustion time to
take advantage of the low emission levels of PCI combustion.
[0029] FIG. 4 depicts five engine operating point transition
scenarios labeled A-E. Operating conditions of the engine are
divided into three combustion modes: the diesel combustion mode
100, the PCI mode 102, and the hysteresis or transitional mode 104.
The switch request 60 is determined based on fuel quantity shown
along the y-axis at 106 and engine speed shown along the x-axis at
108. In an alternative embodiment, the switch request 60 is
determined based on torque and engine speed. The strategy for
determining the switch request 60 is based on the transition
scenarios as described below.
[0030] Scenario A illustrates the fuel and speed requirements for
when the combustion mode remains in the hysteresis area between the
PCI and the diesel combustion modes (no switching occurs). Scenario
B illustrates the fuel and speed requirements for when the
combustion mode switches from the diesel combustion mode 100 to the
PCI mode 102 and remains in the PCI mode 102 for some time.
Scenario C illustrates the fuel and speed requirements for when the
combustion mode switches from the PCI mode 102 to the diesel
combustion mode 100 and remains in the diesel combustion mode 100
for some time.
[0031] Scenario D illustrates the fuel and speed requirements for
when the combustion mode switches from the diesel combustion mode
100 to the PCI mode 102 then switches back to the diesel combustion
mode 100 after only being in the PCI mode 102 for a short period of
time. Upon determination of this scenario, the transition is
actually limited to stay in the diesel combustion mode 100 for a
certain delay period (no actual switching occurs). During this
scenario, the switch request 60 is properly set to reflect this
limitation. This prevents unnecessary switching back and forth to
PCI combustion for only short periods of time.
[0032] Scenario E illustrates the fuel and speed requirements for
when the combustion mode will switch from the PCI mode 102 to the
diesel combustion mode 100 and then switch back to the PCI mode 102
after only being in the diesel combustion mode 100 for a short
period of time. In this case the switching must occur. This is due
to the fact that PCI combustion may only be operated during low
load operating conditions.
[0033] Referring now to FIG. 5, the transition module 52 of FIG. 3
will be discussed in more detail. Because the operating condition
requirements for PCI and diesel combustion are very different, it
is impractical to switch from one mode to the other immediately
after a mode switch request 60 is issued. Therefore, when the mode
switch request 60 is submitted to the transition module 52, the
transition module 52 will coordinate the combustion mode switching
at the right moment and under the appropriate conditions. The
transition module 52 includes a Combustion Mode Switching
Coordination Subsystem (CMSCS) which performs this
functionality.
[0034] As shown in the state diagram of FIG. 5, when the CMSCS
receives a switch request 60 to switch to a different combustion
mode, the mode will first be set to a transitional mode. The
transitional mode can be at least one of a diesel combustion to PCI
transition mode 110 and a PCI to diesel combustion transition mode
112. For example, if the initial mode is the diesel combustion mode
100, after receiving a switch request 60 to switch to the PCI mode
102, the CMSCS will switch the mode to the diesel combustion to PCI
transition mode 110. While in this mode, the CMSCS will check the
air/EGR condition received from the air/EGR estimation module 54 of
FIG. 3. If the air/EGR condition indicates EGR is sufficient, the
CMSCS switches the mode to the PCI mode 102. Otherwise, if a switch
request to switch back to the diesel combustion mode 100 is
received before the air/EGR condition 78 indicates the EGR is
ready, the CMSCS switches the mode back to the diesel combustion
mode 100. This strategy guarantees that the desired combustion mode
is entered only when appropriate conditions such as air and EGR
percentages are achieved.
[0035] Similarly, if the initial mode is the PCI mode 102, after
receiving a switch request 60 to switch to the diesel combustion
mode 100, the CMSCS will switch the mode to the PCI to diesel
combustion transition mode 112. While in this mode, the CMSCS will
check the air/EGR condition received from the air/EGR estimation
module 54 of FIG. 3. If the air/EGR condition indicates the air/EGR
is sufficient, the CMSCS will switch the mode to the diesel
combustion mode 100. Otherwise, if a switch request 60 to switch
back to the PCI mode 102 is received before the air/EGR condition
78 indicates the air/EGR is ready, the CMSCS wilt switch the mode
back to the PCI mode 102.
[0036] Referring now to FIG. 6, the air/EGR estimation module 54 of
FIG. 3 will be discussed in more detail This subsystem includes a
real time predictive estimation sub-module 120 and a target
comparison sub-module. The estimation sub-module 120 estimates a
percentage of EGR and a percentage of oxygen in the intake manifold
based on various measurement parameters such as engine speed, mass
airflow, fuel quantity, boost pressure, intake temperature, and
exhaust pressure. The target comparison sub-module 122 computes a
target value and compares the estimated EGR and oxygen percentages
to the target value to determine if the air/EGR requirements for
PCI or diesel combustion are met. An air/EGR condition is set based
on whether the requirements are met. The air/EGR condition is
output to the transition module 52 of FIG. 3 to determine the
appropriate combustion mode to command for the engine.
[0037] Referring now to FIG. 7, the air/fuel control module 56 of
FIG. 3 will be discussed in more detail. This subsystem controls
air and fuel to the cylinder to achieve smooth transitions during
combustion mode switching. The air/fuel control module 56
determines target values for mass airflow, fuel injection quantity,
and fuel injection timing based on the mode determined by the
transition module 52 of FIG. 3. During the PCI mode and the diesel
combustion mode, the mass airflow, the fuel injection quantity, and
the fuel injection timing is determined based on the engine speed
and fuel quantity (or torque). In an exemplary embodiment separate
mass airflow, fuel injection quantity, and fuel injection timing
lookup tables are implemented for each mode. The lookup tables may
be implemented as two-dimensional tables with engine speed and fuel
quantity (or torque) as the indices.
[0038] During the transition modes, the mass airflow target and the
desired fuel injection timing are determined based on the engine
speed and the fuel quantity (or torque). In an exemplary embodiment
separate mass airflow and fuel injection timing lookup tables are
implemented for each transition mode. The lookup tables may be
implemented as two-dimensional tables with engine speed and fuel
quantity (or torque) as the indices. However, the torque control
sub-system shown in FIG. 7 is adopted to adjust the fuel injection
quantity during the transition modes so that the desired torque is
maintained and a smooth transition between combustion modes is
achieved.
[0039] In FIG. 7, a torque estimation sub-module 124 determines an
estimated torque based on the combustion mode, fuel quantity, mass
airflow, injection time, and engine speed. The estimated torque is
subtracted from a determined desired torque at 126. An inverse
torque sub-module 128 determines a fuel adjustment value based on
the difference in torque and other engine operating parameters such
as engine speed, estimated torque, and combustion mode. The fuel
adjustment value is then added to the actual fuel quantity at 130
and output as a desired fuel quantity. The desired fuel quantity is
then used to control fuel to the cylinder.
[0040] Those skilled in the art can now appreciate from the
foregoing description that the broad teachings of the present
disclosure can be implemented in a variety of forms. Therefore,
while this disclosure has been described in connection with
particular examples thereof, the true scope of the disclosure
should not be so limited since other modifications will become
apparent to the skilled practitioner upon a study of the drawings,
specification, and the following claims.
* * * * *